Keith Moore writes:
| there is another important difference between v4 and v6 - we don't have
| enough addresses for everyone to use v4.
^^^^^^^^ (... at the same time)
That is, either some subset of everyone can use v4 with addresses
which are changed relatively infrequently, or everyone can use
v4 with addresses with relatively short leases that expire as
soon as possible as a device goes dormant.
This is locator-sharing.
| there is another important difference between v4 and v6 - we don't have
| enough addresses for everyone to use v4 [classic].
^^^^^^^^ (... to talk to everyone else)
Or, some subset of everyone can use v4 with globally unique addresses,
or everyone can use v4 with addresses which are only locally unique
(and must therefore use translators to talk to things in other locations).
This is identifier-sharing.
Unfortunately, the overloading of locator and identifier, and
the bad habits that this overloading has engendered in people's
minds, means that neither of these is particularly palatable
at the moment, but neither are they impossible.
I agree that locator- and identifier-sharing are both non-ideal,
but they may be more practical than moving to a system which
still overloads locator and identifier in a flat address anyway.
Sean.